New York (CNN) -- First it was trans fats. Then it was high-calorie fast food. Now, the New York City Health Department is tackling another diet enemy: salt.

The department unveiled an initiative Monday urging restaurants and food companies across the country to voluntarily reduce their products' salt levels, city officials said.

"Salt is a huge problem in our diets," said Dr. Sonia Angell, director of the Cardiovascular Disease Prevention and Control Program at the New York City Department of Health and Mental Hygiene. "The majority of us consume too much salt, which increases blood pressure and puts us at risk for heart attack and stroke."

New York has partnered with cities, states and national health organizations across the country with the goal of cutting the salt in packaged and restaurant foods gradually by 25 percent over five years. Doing that would reduce the nation's salt intake by 20 percent, Angell said.

The average American adult consumes about 3,400 to 3,500 milligram of sodium a day, while most people only need about 1,500, she said. The excess sodium does not come from salting food at the table or while cooking, but from pre-packaged food and restaurant meals, which Angell said amount to nearly 80 percent of the average person's total sodium intake.

"Consumers can always add salt to food, but they can't take it out," Dr. Thomas Farley, the city's health commissioner, said in a written statement. "If we can reduce the sodium levels in packaged and restaurant foods, we will give consumers more choice about the amount of salt they eat and reduce their risk of heart disease and stroke in the process."

The only way to do this, according to Angell, is to get the food industry onboard.

During the past year, city officials have met with industry leaders, company representatives, restaurant owners and health experts to come up with a plan. The result of their meetings is a list of proposed benchmarks for 61 categories of packaged foods and 25 classes of restaurant food to help companies and restaurants nationwide gradually reduce sodium.

Subway, one of the companies that advised the health department, says that it is ready to commit to reducing salt in all Subway locations across the country.

"We have been looking at ways to reduce sodium in all of our products," said Kevin Kane, a spokesman for Subway. "This seemed like an extension of what we were doing already."

The company's most popular product, the 6-inch turkey sandwich, already meets the recommended sodium criteria for the five-year mark. But Kane acknowledged that the chain needs to work on getting some of its other offerings to make the grade without affecting the sandwiches' taste.

Finding that balance between low salt and good taste is not as easy as it sounds. Campbell Soup Company, which has quadrupled the number of its lower-sodium products in the past five years, is not favorable about the initiative simply because of the quick turnaround.

"We feel really strongly that we share the same goal in reducing sodium," said Campbell spokeswoman Julie Mandel Sloves. "However, we think the targets and time frame recommended are quite aggressive."

Sloves said that reducing the salt content can bring out different flavors in foods. Campbell taste-tests all of its new products to ensure that consumers respond positively to any changes, she said, and this would be a challenge in the timeline provided.

While it may take some time to find the correct balance, Angell stressed that reducing salt in a food does not mean reducing flavor.

"If salt is reduced gradually, we won't notice a difference in our palate," Angell said. "Our palate will adjust and we'll enjoy foods as much as we do now."

The campaign against salt is the latest of several health initiatives by New York. In 2006 the city required restaurants to phase out use of trans fats, a goal it said last year had been largely met. The city has also campaigned against high-calorie fast foods and is urging people to choose low-calorie beverages.